Hermetically closed, flexible containers such as plastic bags or liners are frequently used in many applications. For example, in the course of bioprocessing, such bags are often used for bulk intermediate storage, cell culture re-suspension, viral inactivation, final formulation, final fill, or as bioreactors. In many such applications and others, the bag is pre-sterilized, and such condition must be maintained in order to avoid contamination of the product resulting from use of the bag. In the case of bioprocessing, any breach of the sterile condition is considered to be a serious deviation from the conventional protocol, and often results in the discarding of the batch of valuable product, sometimes after significant cost and effort has been expended in the course of making it.
Most bags, including those of the type commonly used for bioprocessing, comprise one or more relatively thin layers of plastic film and thus are prone to damage during shipping and handling. Moreover, the bags often comprise individual sheets or panels of film welded together (such as by heating or ultrasonic means), which can contribute to defects and concomitant leaks along the corresponding seals thus formed. For these reasons, it is highly desirable and perhaps even necessary to validate the integrity of the supposedly sterile bag before valuable product is introduced into it. Likewise, it is also often desirable to check the integrity of the bag after use in order to insure that the integrity of the bag was maintained during the entire period of use (which in the case of bioprocessing can be a relatively long time, such as a few weeks).
Thus, a need is identified for a manner of testing the integrity of a flexible container, such as a bag. The integrity test should be easy to implement (e.g., not bulky or cumbersome), relatively inexpensive, reliable, and should be done in a manner that does not contaminate the interior compartment of the container undergoing testing.